[Metrics] Java metric API (#9377)

java/test/src/main/java/io/ray/test/MetricTest.java

@@ -0,0 +1,87 @@
+package io.ray.test;
+
+import io.ray.runtime.metric.Count;
+import io.ray.runtime.metric.Gauge;
+import io.ray.runtime.metric.Histogram;
+import io.ray.runtime.metric.Sum;
+import io.ray.runtime.metric.TagKey;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+public class MetricTest extends BaseTest {
+
+  boolean doubleEqual(double value, double other) {
+    return value <= other + 1e-5 && value >= other - 1e-5;
+  }
+
+  @Test
+  public void testAddGauge() {
+    TestUtils.skipTestUnderSingleProcess();
+    Map<TagKey, String> tags = new HashMap<>();
+    tags.put(new TagKey("tag1"), "value1");
+
+    Gauge gauge = new Gauge("metric1", "", "", tags);
+    gauge.update(2);
+    gauge.record();
+    Assert.assertTrue(doubleEqual(gauge.getValue(), 2.0));
+    gauge.unregister();
+  }
+
+  @Test
+  public void testAddCount() {
+    TestUtils.skipTestUnderSingleProcess();
+    Map<TagKey, String> tags = new HashMap<>();
+    tags.put(new TagKey("tag1"), "value1");
+    tags.put(new TagKey("count_tag"), "default");
+
+    Count count = new Count("metric_count", "counter", "1pc", tags);
+    count.inc(10.0);
+    count.inc(20.0);
+    count.record();
+    Assert.assertTrue(doubleEqual(count.getValue(), 20.0));
+    Assert.assertTrue(doubleEqual(count.getCount(), 30.0));
+  }
+
+  @Test
+  public void testAddSum() {
+    TestUtils.skipTestUnderSingleProcess();
+    Map<TagKey, String> tags = new HashMap<>();
+    tags.put(new TagKey("tag1"), "value1");
+    tags.put(new TagKey("sum_tag"), "default");
+
+    Sum sum = new Sum("metric_sum", "sum", "sum", tags);
+    sum.update(10.0);
+    sum.update(20.0);
+    sum.record();
+    Assert.assertTrue(doubleEqual(sum.getValue(), 20.0));
+    Assert.assertTrue(doubleEqual(sum.getSum(), 30.0));
+  }
+
+  @Test
+  public void testAddHistogram() {
+    TestUtils.skipTestUnderSingleProcess();
+    Map<TagKey, String> tags = new HashMap<>();
+    tags.put(new TagKey("tag1"), "value1");
+    tags.put(new TagKey("histogram_tag"), "default");
+    List<Double> boundaries = new ArrayList<>();
+    boundaries.add(10.0);
+    boundaries.add(15.0);
+    boundaries.add(12.0);
+    Histogram histogram = new Histogram("metric_histogram", "histogram", "1pc",
+        boundaries, tags);
+    for (int i = 1; i <= 200; ++i) {
+      histogram.update(i * 1.0d);
+      histogram.record();
+    }
+    List<Double> window = histogram.getHistogramWindow();
+    for (int i = 0; i < Histogram.HISTOGRAM_WINDOW_SIZE; ++i) {
+      Assert.assertTrue(doubleEqual(i + 101.0d, window.get(i)));
+    }
+  }
+}